Move around the building head by going left to avoid the mines. Follow the Waypoints, but before entering the tunnel, watch for a Grunt with hand grenades. You can grab one for immediate use.

Go up the escalator and chuck your very first grenade at the Grunts -- make sure the reticule is red before you do. This should satisfy the Kaboom Challenge and get you an Ammo Upgrade for your Tungsten.

Collectible 1

Head up the stairs and go around the corner outside to find the Collectible. Next to it is a train car. Latch on and tug it down to satisfy the Train Wreck challenge. Hop down and kill the three Grunts around the RELAY. Hack it and the area's minefield will become nicely grip-able points for your arm.

Collectible 2

Backtrack now to the first area you were in and swing across the deactivated mines to the Collectible bubble you probably saw earlier. A nearby mine will let you swing right into it without releasing.

Collectible 3

Now go back to the second RELAY area and swing across the deactivated mines to the next Waypoint. Head to the Collectible on the left side. Go inside the building and up the stairs. Rip the train down here, hopefully killing the Grunts below.

Move down the street and hang a left when you can. Head towards the RELAY and move up the train tracks / girders so you can get on the roof above all the Grunts surrounding the RELAY below. Up here is grenade ammunition, so use it on one of the clumps of soldier below. try to get headshots on the others.

Collectible 4

Hack the RELAY and read the entries for some clues to the upcoming Biomech battle. Now, look at the building in the central part of this area. It can be scaled easily by just grappling the sides. Climb it for the Collectible on top.

Collectible 5

From the top of this roof, look down at the deactivated mines past the RELAY. The final Collectible is here. You'll have to swing out to it on the mines themselves. Take the high road, grabbing onto a mine from above the RELAY. Drop to one below towards the direction of the Collectible.

The radiation down here is very dangerous, so be prepared to real in with a tap of Jump to let yourself "cool off" if the screen goes red. At the mine above the Collectible, you'll really get toasted. Take it easy and make your swings perfect to get back to safety -- about 6 mines away towards the direction of the Waypoint.